Sodium hydrogen-5-sulphoisophthalate

Endpoint summary

Link to relevant study record(s)

Reference

Endpoint:

basic toxicokinetics, other

Type of information:

other: expert opinion

Adequacy of study:

supporting study

Study period:

22 January 2013

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Objective of study:

other: toxicokinetic assessment

Principles of method if other than guideline:

Expert judgement in the assessment of toxicokinetic parameters based on available data.

GLP compliance:

no

Radiolabelling:

no

Species:

other: none

Strain:

other: none

Route of administration:

other: oral, dermal and inhalation

Vehicle:

unchanged (no vehicle)

Details on exposure:

see assessment

Type:

absorption

Results:

assumed 100% by inhalation; 50% by oral/dermal

ASSESSMENT

Oral Bioavailability:

The subject material is a water soluble and ionizable material with a measured octanol/water partition coefficient (log) of -1.7 and a moderate molecular weight (MW=268). Such a material should readily dissolve in the gastro-intestinal fluid. However, the presence of ionizable groups will reduce the absorption potential. Given some measured systemic effects in experimental animals following oral exposures, absorption from the gastrointestinal tract cannot be precluded. Once absorbed, the highly ionized nature of the material suggests rapid elimination primarily through the urine. The material should not accumulate or bioconcentrate in tissues. However, to provide a most conservative estimate and for risk assessment purposes, a 50% absorption of the subject material by the oral route is assumed.

Dermal Bioavailability

Compounds most readily absorbed through the relatively impervious stratum corneum skin layer are those of moderate lipophilicity and having both some water and fat solubility. The subject material is highly water soluble but is of a low lipophilicity, as evidenced by a low octanol/wate partition coefficient. Such a material should not be readily absorbed through the skin. However, to provide a most conservative estimate and for risk assessment purposes, a 50% absorption of the subject material by the dermal route is assumed.

Inhalation Bioavailability

Based on the particle size distribution measured for the subject material, inhalation exposure should result primarily in deposition of material in the upper nasopharyngeal reagion of the repiratory tract and with little or no exposure of the alveolar region. However, due to subsequent uptake of the water soluble material into the mucous coating of the respiratory tract with subsequent oral exposure due to swallowing, the material should be considered to be bioavailable by the inhalation route. However, to provide a most conservative estimate and for risk assessment purposes, a 100% absorption by the inhalation route is assumed.

Conclusions:

A toxicokinetic assessment based on the measured and known physical chemical properties of the material and on all available toxicological data was performed. It is concluded that once absorbed from the gastrointestinal tract, the subject material should be rapidly eliminated from the body though the urine. For the purposes of risk assessment, 50% absorption following oral or dermal exposures and 100% absorption following inhalation exposures is assumed. This represents a most conservative estimate.

Description of key information

A review based on expert judgement has been performed on the subject material. For the purposes of risk assessment, 50% absorption following oral or dermal exposures and 100% absorption following inhalation exposures is assumed.

Key value for chemical safety assessment

Bioaccumulation potential:

low bioaccumulation potential

Absorption rate - oral (%):

50

Absorption rate - dermal (%):

50

Absorption rate - inhalation (%):

100

Additional information

Oral Bioavailability:

The subject material is a water soluble and ionizable material with a measured octanol/water partition coefficient (log) of -1.7 and a moderate molecular weight (MW=268). Such a material should readily dissolve in the gastro-intestinal fluid. However, the presence of ionizable groups will reduce the absorption potential. Given some measured systemic effects in experimental animals following oral exposures, absorption from the gastrointestinal tract cannot be precluded. Once absorbed, the highly ionized nature of the material suggests rapid elimination primarily through the urine. The material should not accumulate or bioconcentrate in tissues. However, to provide a most conservative estimate and for risk assessment purposes, a 50% absorption of the subject material by the oral route is assumed.

Dermal Bioavailability:

Compounds most readily absorbed through the relatively impervious stratum corneum skin layer are those of moderate lipophilicity and having both some water and fat solubility. The subject material is highly water soluble but is of a low lipophilicity, as evidenced by a low octanol/wate partition coefficient. Such a material should not be readily absorbed through the skin. However, to provide a most conservative estimate and for risk assessment purposes, a 50% absorption of the subject material by the dermal route is assumed.

Inhalation Bioavailability:

Based on the particle size distribution measured for the subject material, inhalation exposure should result primarily in deposition of material in the upper nasopharyngeal region of the respiratory tract and with little or no exposure of the alveolar region. However, due to subsequent uptake of the water soluble material into the mucous coating of the respiratory tract with subsequent oral exposure due to swallowing, the material should be considered to be bioavailable by the inhalation route. However, to provide a most conservative estimate and for risk assessment purposes, a 100% absorption by the inhalation route is assumed.